# name : dplyr::group lead/next obs (anti-lag)
# key : group.lead
# key : dplyr.group.lead
# key : lead.group
# contributor: Shuguang Sun
# --
group_by(${1:id}) |>
arrange(${2:index}, .by_group = TRUE) |>
mutate(dplyr::lead()) |>
ungroup()